1. Field of the Invention
The present invention relates to an aging apparatus and aging method for performing aging processing on a flexible tube of an endoscope.
2. Description Related to the Prior Art
A flexible endoscope (hereinafter simply referred to as endoscope) is commonly known which has a flexible slender insertion section inserted into a patient's body, piping, and the like. The insertion section of the endoscope consists of a slender flexible tube, a bending section provided at an end of the flexible tube, and a rigid tip section provided at the tip of the bending section. The flexible tube constitutes the most part of the insertion section. The flexible tube is composed of a helical tube made up of a helically wound metal strip, a tubular net for covering the helical tube, and a resin jacket for further covering the outer periphery of the tubular net. Intending the insertion section to be inserted into a complex path, the flexible tube requires excellent flexibility.
In manufacturing the flexible tube, the tubular net first covers the helical tube to form an internal construction. An adhesive is applied to the whole surface of the internal construction. After evaporating a solvent of the adhesive, the internal construction is covered with molten resin to form a jacket. However, the adhesive sometimes seeps into meshes of the tubular net in applying the adhesive, and the adhesive sticking to undesirable portions of the helical tube prevents flexible deformation of the flexible tube. Accordingly, aging process that deforms the manufactured flexible tube into a specified curvature is generally performed for the purpose of removing the adhesive from the undesirable portions.
Japanese Patent Laid-Open Publication No. 2006-000281 discloses an aging apparatus which automatically performs the aging process on a flexible tube. The aging apparatus has a plurality of pulleys over which the flexible tube is looped and a chuck unit for chucking both ends of the flexible tube. Moving the chuck unit carries out the aging process for the whole flexible tube. The locations of the pulleys are partly changeable so that the aging apparatus is available to various kinds of flexible tubes.
In the foregoing aging apparatus, however, the locations of the pulleys are not changed once they have been fixed. In other words, a bending deformation amount (curvature) of the flexible tube is not changed once it has been set. Accordingly, the flexible tube is deformed to a target bending deformation amount from the beginning of the aging process, and undue stress applied to the flexible tube may cause damaging it.